This study was undertaken to determine whether patients with Gaucher's disease and thrombocytopenia could safely undergo invasive procedures (i.e., liver biopsy) under the coverage of the drug Deamino-D-Arginine-Vasopressin (DDAVP) and thereby avoid exposure to blood products. The patients all received pre-procedure screening with CBC, Coagulation screen (PT, PTT, TT, Fibrinogen), LFT'S, BUN & serum creatinine, and assessment of primary hemostasis by Simplate bleeding time. All patients who met the study parameters (platelet count of 50,000 but less than 100,000; bleeding time of 10 min) then received a standard infusion of DDAVP (0.3ug/kg IV over 30 min). A bleeding time was then repeated 1 hour after completion of the DDAVP infusion. All patients who demonstrated a shortening of bleeding time to less than or equal to 10 min then underwent a liver biopsy. Follow-up evaluation of von Willebrand factor and platelet function were subsequently obtained on all patients who received DDAVP to correlate with the response to DDAVP.